RE: [net-next 1/3] net: dsa: optimize tx timestamp request handling

From: "Y.b. Lu" <yangbo.lu@nxp.com>
To: Richard Cochran <richardcochran@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Vladimir Oltean <vladimir.oltean@nxp.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Kurt Kanzenbach <kurt@linutronix.de>,
	Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	"UNGLinuxDriver@microchip.com" <UNGLinuxDriver@microchip.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [net-next 1/3] net: dsa: optimize tx timestamp request handling
Date: Tue, 20 Apr 2021 07:39:40 +0000	[thread overview]
Message-ID: <AM7PR04MB68859C0C52833BF98C5BF55EF8489@AM7PR04MB6885.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20210418151124.GC24506@hoboy.vegasvil.org>

> -----Original Message-----
> From: Richard Cochran <richardcochran@gmail.com>
> Sent: 2021年4月18日 23:11
> To: Vladimir Oltean <olteanv@gmail.com>
> Cc: Y.b. Lu <yangbo.lu@nxp.com>; netdev@vger.kernel.org; Vladimir Oltean
> <vladimir.oltean@nxp.com>; David S . Miller <davem@davemloft.net>; Jakub
> Kicinski <kuba@kernel.org>; Jonathan Corbet <corbet@lwn.net>; Kurt
> Kanzenbach <kurt@linutronix.de>; Andrew Lunn <andrew@lunn.ch>; Vivien
> Didelot <vivien.didelot@gmail.com>; Florian Fainelli <f.fainelli@gmail.com>;
> Claudiu Manoil <claudiu.manoil@nxp.com>; Alexandre Belloni
> <alexandre.belloni@bootlin.com>; UNGLinuxDriver@microchip.com;
> linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [net-next 1/3] net: dsa: optimize tx timestamp request handling
> 
> On Sun, Apr 18, 2021 at 12:18:42PM +0300, Vladimir Oltean wrote:
> >
> > How about not passing "clone" back to DSA as an argument by reference,
> > but instead require the driver to populate DSA_SKB_CB(skb)->clone if
> > it needs to do so?
> >
> > Also, how about changing the return type to void? Returning true or
> > false makes no difference.

Thank you. That's good idea.
And how about letting driver store the skb clone pointer, or not? I copied my comments in patch #3 here,

" Can we totally drop dsa_skb_cb in dsa core? The only usage of it is holding a skb clone pointer, for only felix and sja1105.
Actually we can move such pointer in <device>_skb_cb, instead of reserving the space of skb for any drivers."

> 
> +1
> 
> Thanks,
> Richard